Hormone sprays, such as "Blossom Set", may prevent some blossom drop due to LOW temperatures. However, the resulting fruit are often misshapen. But studies prove that hormone sprays do not prevent blossom drop due to HIGH temperatures.

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The above is from the FAQ at the top of this page and you might be interested in reading the complete FAQ on blossom drop, which you haven't mentioned.

At the day time temps you mention of 60F fruit set should occur, so I'm not sure what the problem might be.

If the temps were high then that could cause blossom drop and lack of fruit set, which isn't the case with your conditions, but pollenization goes fine at 60F.

Blossom Set was devised for use in cool spring areas such as the PNW where pollenization doesn't happen, but the temps involved are much cooler than 60F. It induces what's called Parthenocarpy which means that fruits develop in the absence of pollenization, so fruit development is abnormal. Such fruits lack seeds early in the season and can have a mushy interior and also be malformed, see the qoute above from the FAQ.

The only thing I can think of off hand is that both blossom formation and/or fruit set can be inhibited if plants are growing in too rich soil or are overfertilized with too much N. I don't know if those conditions apply to your tomatoes.

Carolyn

I am in marin so I have had similiar weather. One of my plants (marvel striped) had a ton of blossoms but no fruitset. I gave the plant a shake every day but still no fruitset.

I finally went out with a qtip and just touched each blossom in center to. Within a few days I had about 6 fruitset. Not sure if the qtip helped but who knows.

Thanks for the responses. It thought that it is possible I am over fertilizing -- my previous post was regarding Miracle-Gro Tomato Fertilizer which I am applying once a week to my 8 tomato plants (2 Tablespoons mixed in 2 gallons of water.) However, it turned out I am feeding about half the recommended dose which, as it turns out, is what most tomato growers do.

Well, I guess I am also forgetting that the tomatoes are already growing in Miracle-Gro soil which advertises that I may not have to feed for 3 months. (Could this be it)?

Everything is either growing in container or the Square Foot Garden.

Tammy, I will try the Q-tip on the blossoms tonight.

THANKS!

Back off on the ferts. You're killing them with "food". Sorta like making the kid eat too much and it becomes grossly obese and non-functional.

Anything in containers should get a heavy watering with the idea of "washing out" some of that fertizer. You'll have to hope those in the ground can "get over it".

And what's in the containers??? Is it "soil" or "mix". It should be MIX. NEVER, NEVER put "soil" in containers.

It's time to apply some "tough love" to your plants and make them (let them) use the stuff you've already given them. Again, like the child, it has so many toys it doesn't know which one to play with, so it sits down and cries because it's bored.

No ferts for at least 3 weeks, and then 5 weeks of 1/8 strength what you've been doing, and then 1/2 strength every two weeks after that.

Ted

LOL, thanks Ted.

All of our "soil" is either Mel's mix (in the square foot garden) or MG potting mix with slow release fertilizer for the containers.

I will back off on the fertilizer until further notice.

CORRECTION! I found our first 2 baby tomatoes this morning. This is after doing some pruning last night (I've taken off suckers for rooting new plants.)

So far, these are 2 perfect looking baby Costoluto Genovese tomatoes.

Still, perhaps only a small number of blossoms are setting. A few days ago, I started giving the tomato cages a good shake. But its still something that should happen naturally since we get good breezes in our yard. I have observed the tomatoes getting a good shaking in the wind.

I'm inclined to blame low nighttime temps. The early and cool setting varieties typically set OK in our springs, but the main season varieties tend to hold off till summer to start setting.

I'm no expert, but that's my experience and it's supported by local nurseries and Cal Poly's horticulture dept. *shrug*